1. Field of the Invention
The present invention relates to a backlight assembly and to a liquid crystal display device using the same, and more particularly, to a backlight assembly and a liquid crystal display device using the same, which can reduce edge dark spots occurring in a direct type backlight structure.
2. Description of the Related Art
In general, liquid crystal display devices have been widely employed in the art due to a variety of advantageous features such as light weight, slim shape, low power consumption, full-color implementation and high resolution. Recently, liquid crystal display devices have been utilized in computers, notebooks, PDAs, telephones, TV sets, audio/video devices and the like. In such liquid crystal display devices, the light transmissivity is controlled to display desired images on liquid crystal display panels, depending upon image signals applied to a plurality of control switches arranged in a matrix pattern.
A liquid crystal display device is not a self light-emitting device, and thus, it needs a light source such as a backlight. The backlight for the liquid crystal display device is categorized as an edge type or a direct type according to the position of the light source.
In the edge type backlight, the light source is installed in an edge area of the liquid crystal display panel such that light emitted from the light source is radiated on the liquid crystal display panel through a transparent waveguide plate placed below the liquid crystal display panel. This type provides a good light uniformity, has an extended life span, and is advantageous in fabricating a slim device. In general, this edge type is employed to radiate light on a medium-size or small-size liquid crystal display panel. On the other hand, in the direct backlight type, a plurality of light sources are placed below the liquid crystal display panel such that light emitted from the light source is radiated directly over the entire surface of the liquid crystal display panel. This type of backlight can provide high luminance and is generally used for radiating light on a large-size or medium-size liquid crystal display panel.
Conventionally, a cold cathode fluorescent lamp has been used as a light source for liquid crystal display panels. Recently, researches have been extensively made in order to use an LED lamp as the light source since the LED lamp has advantages such as long life span, lower power consumption, light weight and slim shape. However, the LED lamp has a drawback in that it generates lots of heat as compared with the conventional fluorescent lamp. Therefore, there are problems in that reliability for electric circuits or the like can be degraded due to increase in the internal temperature of a backlight assembly caused by this heat from the LED lamp, and deformation of the parts or cases may be produced due to thermally stresses caused by the internal temperature gradient.